Centrifugal propeller for dirigible balloons



oct; 13, 1931,

R. B. FERRI-:BY

`(JENTRIP'UG'AL PROFELLERFOR DIRIGIBLE BALLOONS rma aan. 14. 1929 O Patented Oct. 13, 1931 BOLL B. FERREBY, 0F LOS ANGELES, CALIFORNIA clam?animan.V raorELLEn son nrnreInLn, mmoorrs Application led January 14, 41939. SeriaINo. 332,537.

My invention is a centrifugal propeller for dirigible balloons.

My 'nventlon pertains to the type of propulsion of a dirigible balloon in which a pro- '5 peller is mounted on thenose of the-balloon and'by the centrifugal action in throwing the air outwardly, causes the forward movement of the balloon. lVarious factors which influence the eiciencyof such a type of pro- ,'10 peller are'in the form lof the blades and also the general shape of the propeller as a whole, together with the constructional shape of the nose of the dirigible balloon and its vstream line form. Y l In the operation of the centrifugal type Iof propeller mounted on the nose of a dirigible balloon, it appears that the propeller throwing the air outwardly by centrifugal force and as it can only suck air in at the center of' rotation in front of the nose of the.

balloon, creates a partial vacuum in front of the nose. y The outwardly blown air instead of transversing outwardly in the plane of the propeller, follows the curvature of the nose and the stream line form of the dirigible, the

, balloon as awhole developing' a forward motion varying in speed apparently with the volume of air thrown out by the centrifugal force and the velocity of such air.'A

.lo An object of my invention is in the construction and'mounting of such a propeller so that a large amount of air is thrown outwardly by thecentrifug'alforce and this air has a high velocity.

Another ob]ect of my invention is to prevent the escapage of -air from being acted on by the propeller blades so that these blades ositively act on a volume o f air coming with- 1n their sweep and reduce the eddy currents 40 which interfere with the How of air outwardly on the blades.

My invention may be considered as animprovement on my atent application for a centrifug-al blower or dirigible balloon Serial No. 283,347 filed -J une 6,1928.

A further object of my invent-ion 1s in making the propeller blades .somewhat troughshaped in cross section and preferably increasing the width of the trough from tle e0 base tothe tip of the blades. l I

' tion of the trough facing `air operated on bythe PATENT oFFlcls:l-l r4 l.Another object of my invention is in mountl ing the blades at a slight tilt so that the lead-,` ing edge of a blade is positioned slightly rearwardly of a portion of the trough'. The forward portion of the blade therefore functions somewhat as the camber o'n a ating a' slight vacuum by the ow of air on the leading or forward surface, ,l

In constructing myl invention I utilize a suitable type of hub which ma be secured to the propeller shaft and refera ly has a series of substantial spokes. e blades are riveted 'or bolted to these spokes and each blade is of a trough-like construction with the open porin the direction of rotation. The forward side of each blade, that is the side towards the ,direction of travel of the dirigble balloon,

ahead in the direction rotation than the rearward edge of each blade, that is on the `opconcave curvature following the shape of the nose of the dirigible balloon and are designed ropeller, cre- 1 ist positioned slightly o to` have but slight clearance so that all ofthe propeller will be thrown out by centrlfugal orce. The blades may be designed with a large end out,l thatv is at the tip and a small root connected to the hub; or they may be constructed in an opposite manner with arelatively large root and a small tip. l y l My `invention is illustrated in the accompanying drawings, i'n which;l

Figure 1 is a' frontl levation of substany tially half of'a propeller, showing a type with the blades having the tips larger than the root;

Fig. 2

shown in Fig.1; l Fig. 3 is a rear'view of the propeller; of

is Va side elevation of a propeller lll dll

Fi' l is o section on the line l--d of Fig. l in e direction oi the arrows; l Fig. is a @ont elevation oi an alternative form of propeller, in which the'tipl'of the blade is smaller than the root;

Fig. Fig. 5;

Fig. I is a rear elevation ,of a propeller oi Figs. 5 and 6;

Fig. 8 is a section on the'line 8-8 of Fig. 5 in the direction ot the arrows. v

Referrin irst'to Figs. l; through 4 the propeller s ait ll has a substantial lhub 12A secured thereto, this being the hub oi the propeller, and on this hub l have a' plurality oi spokes 13 of a' substantial character'and of suitable shape. To these spokes are secured the blades designated generally by the numeral la oi the propeller and on the front there is a cone-sha ed spinner 15 for the purpose of deectin t e air and giving a more or less stream like om and to enclose the spokesand the hubo The characteristics of the blade ld is the trough-like construction indicated by the numoral 16 and the leading edge l? is -lorward ot the trailing end l8 ol each ot the blades. The troughs may be of diderent depths. The extreme forward surface l@ ci each .el the blades considered in the direction of nuovement or the balloon ispositioned slightly lorward of the leading edge l'l. The line 20 designates the plane oi' rotation ol the extreme forward portion i9 oi" the blade and 2l the planeA ol the rotation of the leading edge l?, these being considered et any particular cross section. llhereiorethe surface lll may be considered as having a lead designated by the measurement 22 in iront ol the leading edge l?. The inner portion 23 ci the trailing edge 18 is carried slightly forward ci' the inner portion td ol the leading edge l?.

The trailing edge also has a concave curvature as indicated at Q5, conforming somewhat to the curvature 26 or the nose 2? of the dirigible balloon. ln this type ot blade the root 28 is of lesser sise than the tip @dei the blade and if desired the trough may vary in depth lfrom.V the root tothe tin and manifestly it varies in width between the leading and trailing edges from the root to the tip of the blade.

In the constructionil'lustrated in Figs. 5

i through 8, the blade has the root portion 30 of greater size than the tip nortion 3l. "lhe leading. edge 32 is forward of the trailing edge 33 and the leading edge is slightly back from the extreme forward portion 34 of the body of the blade. The trough section 35' may vary in depth from the root to the tip of the blade and the distance between the leading and trailing edges decreases from the root to the tip.. The trailing edge infthis case has a concave curvature 36 conforming to the curvature of the forward surface 3'? neonato construction also necessitates the forward portion oi the blade having a convex curvature 39- on account of lthe blades tapering hom the root to the tip and followin the curvature of the nose of the dirigible ba oon. 6 is aside elevation of a propeller oi rection ol .rotation is so that the trou h catches the air and such `air is held in t e trough while it travels longitudinally of the blade from the root towards the tip. As the velocity of the tip of the blade is considerably greater than lthat of the root, the air becomes hi bly com ressed and. is thrown outwardly y centri gal force so that the how of air 'from each blade more or less acts as distinct outwardly Howin columns. As

ln the operation of my propeller, the dithe blades are rotating rapidily, these merge together and cause a direct outward movement of air considered radially Jfrom the axis of rotation. As the air can only be drawn into the propeller from the front, this creates a artial vacuum, tending vto draw the dirigible balloon ahead.. v

lt has been found that the stream oi air clings to or follows the surface of the dirigible balloon when this is properly stream lined somewhat in the manner as set forth in my patent a plication above inen-` tioned. 'lhe combine action of the centriugal air blast is to move the dirigible balloon in a forward direction.

The feature oi having the leading edge gli slightly rearward or towards the nose olf the balloon in relation to the extreme forward portion l9 ci the blade, appears to give this *portion a spacious or aeroioil edect, such as the upper surface ot the conventional aeroplane wing creating a partial vacuum in iront ol' the leading edge of the trough-like blade, functioning to draw the dirigible balloon forwardly. ln addition, on account-oli the forward motion of the translation oi the propeller as a whole, the leading edge oi the trough-lilac blades catches the air and does not allow this to form eddies blowingaround the leading edge on to the bach' surfaceoi the blade. Y l

ln the construction of Fi s. l through Il,

in which the tip oi the bla e is wider than the trough, the function is to spread the column of air dischar ed from eachA blade in a lore and aft direction and thus give outwardl moving air streams which may. be consi` ered as' comparatively shallow and haying a lesser velocity than when the tip 55 ofthe nose 38 of the dirigible balloon. Valious changes maybe mdn the prim Slt lGC

lll@

jacent from the spirit thereof as set forth in the description, drawings and claims.

l.. .A propeller for dirigible'balloons having a plurality of centrifugally acting trough-shaped blades adapted to be driven by a rotary shaft, each of said blades having the leading edge forward of the trailing .edge considered in the direction of rotation and the leading edge being turned rearwardly considered in relation to the forward movement ofthe propeller from the side structural part of the trough of each blade.

2. A progcller for dirigible balloonsas claimed 1n c aim 1, the trough of each blade varying in cross section from vthe root tothe tip of the blade.

3. A propeller for' dirigible balloons as claimed in claim 1, the trailing edge of the blade being free of a support and having a vconcave curve ina fore and aft direction.

1. A propeller for dirigible balloons, comprlsing a plurality of centrifugally acting trough-like blades with means to secure same to a rotary shaft, e'ach of said blades having aleading and a trailing edge, the trailing edge being concave considered in a radial direction, the leading edge of the blades beingforward of the trailing edge considered in the direction of rotation of the blades.

5. A propeller for dirigible balloons as claimed in claim 4, said leading edge being turned lrearwardly considered in the direction of the forward movement of the propel-` ler from the side of the trough of each of the blades and the trough of each of the blades pro eller shaft extendincg through the nose an a ropeller mounte thereon, said proeller having trou h-like blades, the center ine of each blade ing substantially radial to the shaft, each blade havin a lea ing and trailing` edge, the trailing e ge conforming to the convex shape of the nose of the balloon and the leading edge bein ahead of the trailing edge in the direction o rotation and rotating in close proximity to such convex nose.

9. In a device as described, as clalmed 1n claim 8, the leadingedge of the blade being rearwardly of the leading side of the trou h-like blade considered in the direction of t e forward movementof the propeller through the air. v

10. A propeller for dirigible balloons comprising a shaft having a lplurality of centrifugally acting trough li e blades secured thereto, each of the blades havin and a trailing edge, both of sai edges being free of support, the sole support ofthe blades being the connection to the shaft, and the said trailing edge being concave considered in the fore and aft direction of the movementI of the propeller as a whole through the air.

In testimony whereof I have signed my name to this specification.

' ROLLA B. FERREBY.

positioned slightly varying in cross section from the root to the tip.

6. In a' device as described, the combination of a structural portion of a dirigible bal'-1 y loon having a-convexly shaped nose, a centrifugally'acting propeller mounted on a rotatable shaft extendingaxially through' said nose, the propeller having trough-like blades, said blades having a leading and a trailing edge, the trailing. edge being curved to conform to the shape of the nose of the balloon and rotating in close proximity to such convex nose. y

7. In a device as described, the combination of a structural:A portion of -a dirgible balloon having a convexly curved nose, a propeller shaft extending through the nose and a propeller mounted thereon, said propeller havingtrough-like blades, Athe center lineof each blade being substantially radial 5to said shaft, each blade having a leadingl vand trailing edge, the trailing edge conforming to the convex shape 'of the nose of the balloon and rotating in close proximity to such convex '.nose. A

8. In a device as described, the combination of a structural portion of a dirigible balloon vhaving a convexly curved nose,'a 

